Mechanical refrigerating system



3mm 1943 w. JOHNSON :FAL 2,32%,w

MECHANICAL REFRIGERATING SYSTEM Filed. Dec. 4. 1946 3 Sheets-Sheet 1 97a fl' 7E ATTORNEY.

IN VENTORfi I Jana 15, 1943- R, w, JOHNSON L I 2,321,819

MECHANICAL REFRIGERATING SYSTEM Filed. Dec. 4 1940 I 3 Sheets-Sheet 2 A]@Hllil V,

BY Elarancs LfiugZ-LE W w ATTORZIi INVENTORSZ 25S Hg ZrzLJUhnsc/n gum R.w. JOHNSQN ETAL MECHANICAL REFRIGERATING SYSTEM,

Filed. Dec. 4, 1940 Sheets-6219s; 5

BY Elararzae Lflu he INVENTORSII Patented June 15, 1943 I MECHANICALREFRIGERATING SYSTEM Roy W. Johnson and Clarence 'L. Aughey,Milwaukee,-Wis., asslgnors to Automatic Products Company, Milwauk ofWisconsin ee, Wis., a corporation- Application December 4, 1940, SerialNo. 368 ,5l

9 Claims.

This invention relates in general to mechanical refrigerating machinesor systems, and more particularly to a vapor compression refrigeratingmachine wherein a liquid is used which can be V into a receiver, and aliquid supply line leads from the receiver of the inlet to theevaporating or cooling coil. An expansion valve is provided in theliquid supply line adjacent the inlet to the cooling or evaporating coilto produce the desired throttling effect.

,Such refrigerating systems are commonly employed in commercialinstallations, household refrigerators, and the like. the cooling coilbeing disposed in the refrigerator box or receptacle, or in heatinterchanging relation to the compartments thereof which containsubstances to be kept cool, the refrigerator or evaporating coils,

functioning to absorb the heat coming into the box in order to keepthe-box at a predetermined temperature. The refrigerant which flowsthrough the coils to absorb the heat is' at most times below thefreezing point of water, and, therefore, during ,the cooling cycle themoisture in the box or fixture will freeze and accumulate on the surfaceof the coil, forming frost or ice. After a period of time, thisaccumulation of frost or ice will build up to such an extent that thecoil becomes lneflicient. It is good practice to eliminate this frost orice from th coil surface by melting the same. Such melting operation iscalled defrosting-." One method of defrosting is to isolate t'le coilfrom the refrigerating system by stopping the refrigerant from passingthrough the coil, thereby letting the pressure build up in the 'coilwith a corresponding increase in temperature whereupon the ice on theexterior surface thereof will melt quit readily.

The object of the present invention is to prothe compressor. and is socombined with the suction line that the outlet connection of the coil isconnected to the inlet to the control valve whereas the inlet or suctionconnection of the compressor is connected with the outlet of the controlvalve.

The control valve is so constituted that when open it allows free flowthrough the suction line from the cooling coils to the compressor, butwhen it is closed it blocks all flow therethrough, thereby effectivelyisolating the cooling coil from the compressor. This control valve isautomatically regulated in its action under the conjoint influence ofthe coil temperature and box or receptacle temperature, and in suchmanner that while the selected box or receptacle temperature will bemaintained, the'coil will bedefrosted on each refrigerating cycle.

In exercising this automatic regulation, the

will be opened, whereas when its supply is cut off the valve will closeunder the biasing action of its spring.

Operating mechanism is provided for the pilot valve. and preferablycomprises a pilot valve-operating lever'connected to an actuating arm ofthe pilot valve and swingable to open or close the pilot valve.

Means is provided for swinging the pilot valveoperating lever to eitherone of its two positions, and this may advantageously comprise a togglelever and spring mechanism which is reversible in the direction of itsaction, and which is combined with the valve-operating lever so thatwhen acting in one direction it opens the pilot valve. and when'acti inan opposite or reverse direction it tendsto c ose the pilot valve. Thedirection of action of the toggle lever and spring mechanism iscontrolled by means of a thermostat whichis responsive to the coiltemperature; The thermostat is so combined with the toggle lever andspring mechanism that upon a rise in pressure in the coil it will actupon the'toggie lever and spring mechanism to cause it to act in adirection to open the valve, and in exerting this action .upon thetoggle lever and spring mechanism the thermostat lsoppcsed in its actionby a spring. Upon a decrease or fall of pressure in the cooling coil thethermostat allows the toggle lever and spring mechanism to be reversedin position. An adjustable spring acting upon the latch biases it toreleased position. With this construction upon a predetermined rise intemperature in the box or-fixture the thermostat will overcome theaction of the associated spring and will move the "latch to latchingposition so that if the valve-operating'lever is in, or is moved to,pilot valve-opening position, it will be releasably latched in suchposition until the box or fixture temperature has decreased to aselected value, namely one which will allow the action of the thermostatto be overcome by the action of the associated spring.

Other objectsand advantages reside in certain novel features of theconstruction, arrangement, and combination of parts which will behereinafter more fully described and particularly pointed out in theappended claims, reference being had to the accompanying drawingsforming a part of this specification, and in which:

Figure 1 is a diagrammatic view in elevation illustrating a vaporcompression refrigerating system with the present invention embodiedtherein;

Figure 2 is a view in longitudinal, vertical cross section taken on line22 of Figure 3 and illustrating certain features of the construction ofthe control valve incorporated in the suction line between the coolingcoil and compressor in accordance with the present invention;

Figure 3 is a view partly in end elevation and partly in transversevertical cross section further illustrating the control valve, partsbeing shown in elevation for the sake of simplicity in illustrat on; I

Figure 4 is a view in longitudinal vertical cross section taken on line4-4 of Figure 3 and looking in the direction of the arrows; 1

Figures 5 and 6 are detailed perspective views of the two members whichgo to make up the lever for the pawl or latch;

, Figures 7 and 8 are detailed perspective views illustratingrespectively the toggle lever and the valve-operating lever;

Figure 9 is a diagrammatic view showing the various positions assumed bythe valve-operating lever, its toggle and spring mechanism, and thelatch and its lever in the defrosting and re- I frigerating cycles; and

Figur 10 is a detail perspective view of the pawl or detent of thelatch, its associated spring, and stop screw.

Referring to the drawings, and more particularly to Figure 1, whereinthe invention is diagrammatically illustrated as embodied in a vaporcompression refrigerating machine, the numeral ll designates a coolingcoil which is combined in pansion valve 16, the outlet fitting of whichis connected to the inlet of the cooling coil I ll. A suction line Hconnects the outlet of the cooling coil [0 to the inlet or suctionof thecompressor 12. The present invention proposes to incorporate a controlvalve, designated generally at C, in the suction line.

As illustrated in Figure 2, the control valve C comprises a main valvecasing 20 having an inlet fitting 2| connected to the outlet of the coilIII and an outlet fitting 22 connected to the suction of the compressor.Interposed between the inlet 2| and outlet 22 the valve is provided withan in ternal ported partition 23, the lower side of which is formed withan annular valve seat 24. On the underside of the partition 23 the mainvalve casing is formed with a valve chamber 25 extending through thebottom thereof. A removable valve plug 26 is interthreaded withthe'lower end of the valve chamber, and, when applied, is hermeticallysealed thereto by means of a sealing washer 21. A main valve 28 isdisposed in the,valve chamber 25 in cooperative relation to the valveseat 24 of the ported partition 23. Pref erably the head of the valve 28is. provided with a valve facing 29 which is secured in place by aretaining ring 30. The valve 28 has a downwardly extending stem 3| whichis guided in a tubularvalve guide 32 formed, if desired, as an integralpart of the plug 26. A coil spring 33 encircles the guide 32, has itslower end abutting the plug 26, and has its upper end bearing upvidedand discharges into a condenser l3, which in turn discharges into areceiver II. A liquid supply line l5 leads from the receiver to anexwardly against the under side of the head of the valve 28 to bias thevalve to closed positionthat is, to position wherein its facing 29 hassealing engagement with the valve seat 24.

Above the partition 23 the main valve casing 20 is provided with anoutlet chamber 35 which.

extends through the upper end thereof. The top of the main valve casing20 is appropriately machined around the margin of the upper end of theoutlet chamber 35 to adapt it to be interfitted with a pilot valvecasing 36. A sealing gasket 31 is interposed between the pilot valvecasing 36 and the main valve casing 20, and these parts are heldassembled by a suitable number of cap screws 38 (see Figure 3).

, A fluid pressure motor is provided for opening the main valve 28 andmay comprise a bellows 33 accommodated in the outlet chamber. 35. The

upper end of the bellows 39 is mechanically engaged with andhermetically sealed to a depending annular extension 40 of the pilotvalve casing 36. The lower end thereof is mechanically connected andhermetically sealed to a bellows cup 4|. The bellows cup 4| has acentral portion bearing against the upper end of a pin-like extension 42of the valve stem 3i so as to provide a motion transmission trainbetween the fluid pressure motor and the main valve 23.

The pilot valve casing 36 is formed with a pilot valve chamber 43. inwhich a pilot valve 44 is slidably fitted. The pilot valve 44 has a bodyportion 45 of non-circular cross section but having peripheral surfaceswhich slidably engage portions of the inner peripheral surface of thevalve chamber 43, other peripheral portions of the pilot valve body 45being, however, spaced from the inner peripheral surface of the valvechamber 43 so that fluid may flow freely from one side of the pilotvalve body 45 to the other, and also from either side of the pilot valvebody 45 to an annular groove 46 formed in the central peripheral portionof the valve body. The pilot valve 44 is in reality two valves with acommon body 45, for at one end of the pilot valve body is an inlet valvemember 41, whereas at the opposite end of the pilot valve body is anoutlet valve member 46. These valve members 41 and 48 coact withapertures or ported valve seats 49 and 50, respectively.

The valve seat 49 is carried at the inner end of a high pressure inletfitting threaded into the pilot valve body and hermetically sealedthereto by a gasket 52. A high pressure line 53 connects th s highpressure inlet fitting 5| with-a suitable source of fluid under pressurewhich may conven- The port of the outlet valve seat 50 communicatesthrough a chamber 54 and a passage-way 55 with the outlet chamber 35. 7

When the p lot valve 44 is positioned as shown in Figure 2, the supplyof pressure to the fluid pressure motor is cut off, and any pressuretherein is exhausted through the port 56, which provides forcommunication between the interior of the bellows motor 39 and the pilotvalve chamber 613. From the port 56, the fluid under pressure passesinto groove 46, thence along the spaces between the periphery of pilotvalve body 45 and the inner peripheral wall of valve chamber 43 to theport of the valve seat 50, chamber 54, and passage 56, to the outletchamber 36 of the main valve cas ng 20. On the other hand, if the pilotvalve 44 is shifted so that its valve member 48 closes the port throughthe valve seat 59 and opens the port through the inlet valve seat 49,then fluid under pressure willflow through the high pressure line 63,inlet fitting 5|, ported valve seat 49 to the valve chamber 48, thencearound the periphery of the pilot valve body 45 through the annulargroove 46 and port 56 into the interior of the bellows motor 39. "Thebellows 39 will with the central portion of the body 45 of the pilotvalve. Anintermediate portion of the valveactuatng arm or lever. 60 hasa ball and socket or un versal mounting 62 in a packing gland 65threaded into the pilot valve casing 36 and hermetically sealed theretoby means of a washer 64. A sealing bellows 65 is provided and has oneend mechanically connected and hermetically sealed to the arm soadjacent to its universal mounting t2 and has its opposite end similarlyconnected and sealed to the gland 63. The an. 60 projects rearwardlyfrom the p lot valve housing and into a control box 66 which containsthe most of the elements of the mechanism which provide for theautomatic operation of the pilot valve 44 and the consequent automaticoperation of the main valve 26. 1

As illustrated in Figures 3 to 9, inclusive, this mechanism comprises avalve-operating lever, designated generally at 61. The lever 61 may beadvantageously stamped from sheet-metal, and when so constructed themain portion of the lever, designated at 68, is of channel shape (see,

Figure 8), the side flanges of the channel bein indicated at 69 and 10and the body portion thereof at 1|. The body portion is provided with acut-out or rectangular slot 12 for clearance purposes, as willhereinafter appear. The lower ends of the sideflan'ges 69 and 10 havetransversely alined openings 13 to facilitate the i'ulcruming of a leveron a pivot pin 14, which is mounted in a pivot pin bracket 15 suitablysecured as at 16 and 11 in the control housing 66. The flange 10 of thelever has an extension 11 which is formed with an aperture 18 throughwhich the actuating arm 60 of the pilot valve extends. The upper end ofthis extension is bent laterally and then downwardly to form a pointedlatching projection 19. The upper end-of the body of the lever isprovided with an integral inturned lug 80 carrying a pointed projection6| for the purpose which will presently appear. Mechanism is providedfor shifting the lever 61 to cause it to swing the actuating arm 60 andconsequently move the pilot valve 44 to open or closed position.

The pilot valve 44 is cons dered to be in open pos tion when its valvemember 48 closes the ported valve seat 50 and the valve member 41 isspaced from and opens the valve seat 49 so that fluid under pressure issupplied to the bellows motor 36 and the main valve 28 is also opened.The closed position of the pilot valve is that shown in Figure 2 whereinfluid under pressure is exhausted from the bellows motor 39 and the mainvalve 28 is closed.

A reversible acting toggle lever and spring mechanism is preferablyprovided for shifting the lever 61 to either of it two positions andcomprises a toggle lever 82 which also. may be constructed of sheetmetal and is of channelshaped form (see Figure 7), with the lower endsof the flanges of the channel provided with transversely alinedapertures 83. The toggle lever 62 is of; less width than thevalve-operating lever 61 and is disposed between the side flanges 69 and10 thereof. and is mounted upon the same fulcrum p n 14 as thevalve-operating lever 61.

the pin 14 passing through the apertures 83 of the toggle lever-82 forthis purpose. The body portion of the toggle lever 82 has an integralinturned lug 84 at its upper end, the lug 84 also carryin a point ofprojection 85.

In Figure 4, the projections ill and 85 are shown as intezral with theirrespective levers 61 and 62, and wh le these parts may be fashioned inth s manner, it is preferable to have the projections 80 and 85 ofseparate pieces of hard steel and suitably secure them to their leversas il ustrated iI Figures 7 and 8.

I". the assembly the projections Bi and 85 are in confronting relati nand engage spring cups 86provided at the ends of a toggle spring 81,

which is compressed between the cups and consequently s inte posedbetween the toggle lever and the valve-operating lever.

By shift ng the position of the toggle lever 82 relative tothe'valve-operating lever 61, the action of the toggle spring 81 may be.reversed. In the position shown in Figure 4, the toggle lever 82 is soangularly related to the valve-opera-ting lever 61, and the spring 81 isconsequently so incl ned or positioned, that the force of the spring 8tends to, urge the valve-operating lever 61 in a counterclockwisedirection as viewed in Fi ure 4. thereby shifting the arm 60 in suchdrection as to open the pilot valve 44. If now ihe t ggle lever 62 isswung in, a counter-clockwise d'rection with respect to thevalve-operating lever 61, or to a position such as shown in Position, 1in the diagram, Figure. 9, the action of the spring 81 will be reversedand it will urge the valve-operating lever 81 in clockwise direction asviewed in Figure 4, thereby so moving the arm 88 as to move the pilotvalve 88 to closed position.

The position of the toggle lever 82 is controlled .by means of athermostat, designated generally at 88, and adjustable spring means,designated at 88. The thermostat 88 comprises a bellows 88 mounted onthe control box housing and combined with the conventional-capillarytube 8I and bulb 82. The bulb 82 is in intimate contact and in efllcientheat interchanging relation with the cooling coil I8.

The bellows 88 is of conventional construction and includes a housing83, bellows proper 88, and driving projection 85, the pointed end of thedriving projection engaging in a seat or conicaldepression 82' in thebody of the toggle lever 82.

The adjustable spring means 88 comprises a compression spring 88 havingone end engaging the convex wall of the seat 82' and having its otherend bearing against a nut 81 threaded-on a fixed screw- 88 so as to beadjustable thereon to vary the compression of the spring 88.

With this construction, when the tempera ture of the coil I8 increases,the fluid in the bulb 82, capillary tube 8|, and bellows 88 increases,and this increase in pressure forces the driving projection 85 to theright as viewed in Figure 4, and when it has increased to a predetermined amount, depending upon the compression of the spring 88, thetoggle lever 82 will be moved to the position shown in Figure 4, .and

. the spring 81 will thereupon so move the valvetothe positionillustrated as Position 8 in Figure 9, whereupon the spring 81 will tendto swing the valve-operating lever 81 in a direction (counter-clockwise)to close the pilot valve 88.

Whether or not the spring 81 will effect openingof the valve 88 underthe conditions just described depends upon the position of a latch,designated generally at I88. Thelatch I88 comprises a pawl or detent I8Ipivotally supported as at I82 on an arm I88 of a latching lever,designated generally at I88. A blade spring I88 urges the pawl I8I tolatching position, and its ever, this action is opposed by adjustablespring means, designated generally at III. This adjustable spring meansIII comprises a coil spring II2 having its lower end bearing on andsuitably interfitted with a spring seat provided therefor on the outerend of the arm I88 of the latching lever. A spring cup II8 engagestheupper end of the coil spring I I2 and is engaged with a pointedprojection II8 formed at the lower end of an adjusting screw H5. Thescrew H8 is threaded into an internally threaded bearing II8 carriedatthe top of the control casing and is equipped at its upper end with acup 1 to facilitate its adjustment.

Typical phases of the operations involved in a defrosting andrefrigerating cycle are diagrammatically illustrated in Figure 9. InFigure 9 eight phases of the operation, or eight different positions ofthe control mechanism, are illustrated, and the several positions arerespectively designated by the numerals l to 8 enclosed in circles.

Position 1 in Figure 9 shows the control mechanism at the start of thedefrosting cycle. Due to the low temperature in the coil I8, a lowtemperature exists in the bellows 88 and it is in a contracted position.The defrosting spring 88 consequently forces the toggle lever 82 in acounter-clockwise direction, as viewed in Figure 9, and this so inclinesthe toggle spring 81 that it biases the valve-operating lever 81 torotate clockwise, as illustrated in Figure 9. The latch I81 beingreleased the valve-operating lever 81 will move the pilot valveactuating arm 88 in such man- 'ner as to close the pilot valve 88 andconsequently Defrosting bellows 88 starts to expand, due to the riseinpressure caused by the rise in coil temperature, and this expansion ofthe defrosting bellows 88 forces the toggle lever 82 to rotate in aclockwise direction, as viewed in Figure 9,

against the action of its associated spring 88, thereby moving thetoggle spring 81 closer to dead .center.

Position 3 in Figure 9 shows the control mechanism in the third stage ofdefrosting with the pressure in the defrosting bellows 88 such thatmovement to latching position under the influence of this spring I85 islimited by a stop screw I88. The latching lever I88 includes a second.arm or member I81, these two arms being con- The arrangement is suchthat when the tem perature in the box or fixture II' increases, acorresponding increase in the pressure of the fluid in the bellows ofthe thermostat 8 tends to swing the latching lever I88, and consequentlythe latching pawl IN, to latching position. Howthe toggle lever 82 is ondead center with the valve-operating lever 81.

Position 4 in Figure 9 shows the control mechanism in the last stage 01'the defrosting cycle. The pressure in the defrosting bellows 88 hasovercome the force of the defrosting spring 88 with the consequence thatthe toggle lever 82 passes the dead center of the valve-operating lever81, thereby putting the toggle spring 81 in such position that it isbiasing the valve-operating lever 81 counter-clockwise, as viewed inFigure 9.

Position 5 shows the control mechanism at the same time period, but thevalve-operating lever 81 has moved counter-clockwise, as viewed inFigure 9, due to the action of the toggle spring 81 exerting a force inthat direction. Valve-oper ing the refrigerating cycle. l'it the sametime the pointed latching projection I9- of the valveoperating lever 61engages the pawl or detent I! of the latch I00 since the latch is now inlatching position, for the reason that as the defrosting cycleprogresses the box or receptacle temperature rises, thereby increasingthe pressure in the to rotate the toggle lever 82 in counter-clockwisedirection, thereby bringing the toggle spring 81 closer to dead center.

Position 7 shows the control mechanism in the second stage of therefrigerating cycle. The coil temperature is decreased so the defrostingbellows 90 has contracted to the point that the defrosting bellows 90has allowed the toggle lever 29, underthe influence of its spring 96, tobring the toggle spring 8'! to the position of forcing .thevalve-operating lever 61 to the pilot valve closingposition. But if thebox or receptacle temperature is not low enough, the box temperaturebellows ,IIO will keep the pawl lever I00 of the latch I00 in suchposition that its pawl or detent "I will remain engaged with the pointedlatchving projection 19 of. the valve-operating lever 01, therebylatching the valve-operating lever in'pilot valve open position.- Thebox or receptacle temperature must drop to a point at which the boxtemperature bellows H0 will contract sufliciently to allow the boxtemperature adjusting spring means III to force the pawl lever I04 ofthe latch I00 in a clockwise direction, as viewed in Figure 9, therebyallowing the detent IN to disengage the latching projection 19, therebypermitting the lever 61 to snap over to valve-closing position, as shownin position 1,

for the purpose of illustration or example, and that various changes'inthe size, shape, and arrangement of the parts may be made withoutdeparting from the spirit of the invention or the scope of the subjoinedclaims.

We claim:

1. In a refrigerator of the type wherein the refrigerating effect isobtained by virtue of the passage of a refrigerant through a coolingcoil disposed in heat interchanging relation to the compartment of therefrigerator, a control valve combined'with the cooling coil so as topermit flow therethrough when opened and block flow therethrough whenclosed, a reversible operating mechanism for said valve, said operatingmechanism biasing the valve to open position when acting in onedirection and jtoclosed position when actingin the reverse direction, athermostat subjected to the temperature of the cooling coil and combinedwith said operating mechanism to cause the same to bias the valve toopen position upon predetermined rise of pressure in the coil and toclosed position upon predetermined fall of pressure in the coil, aflatchcooperable with the operating mechanism and adjustable from a latchingto a releasing position, said latch functioning when in latchingposition and when the valve is in open position to hold the operatingmechanism andthe valve in valve open position, and a thermostatsubjected to the temperature in the compartment and combined with thelatching mechanism to move the same to latching position uponpredetermined rise in temperature in the compartment and to provide forthe movement of the latching mechanism to released position uponpredetermined fall of temperature in the compartment.

2. In a refrigerator of the type wherein the refrigerating efiectis-obtained by virtue of the passage of a refrigerant through a coolingcoil disposed in heat interchanging relation to the compartment'of therefrigerator, a control valve combined with the cooling coil so as topermit flow therethrough when opened and. block flow starting thedefrosting cycle and completing the refrigerating cycle.

The defrosting temperature depends upon the rate at which the coil I0can become defrosted. 36 F. is a typical temperature. If the ratio ofcoil surface to box or receptacle content is such that a greater amountof.ice accumulates on the coil, a temperature higher than 36 F. will berequired, Conversely, if there is a small amount of frost and iceaccumulated on the coil, a lower temperature will completely defrost thecoils. Therefore, a defrosting temperature adjustingv means, constitutedof the spring 96 and a screw 90, is provided to vary the compression ofthe defrosting spring 96, so as to increase or decrease the temperatureat which complete defrosting is accqmplished. v

Box or receptacle temperature may also be variable and must be held ,atthe required temperature selected. Therefore, a temperature adjustingknob H1 is provided so that the proper box or receptacle temperature canbe had by adlusting the knob I H to the usual or suitable temperaturemarkings on the indicator conveniently associated with such a controlknob;

While we haveshown and descrlbedone construction in which the inventionmay be advantageously embodied, it is to be understood that the'construction shown has been selected merely therethrough when closed, apilot valve to control the action of the main valve, an operating 'leverfor said pilot valve, a reversible toggle lever and spring mechanismcombined with said valve operating lever effective when acting in onedirection to shift the lever to one of its positions and 'when acting inthe opposite direction to shift the lever to the other of its positions,a thermostat subjected to the temperature of the cooling coil andcombined with the reversible toggle lever and spring mechanism tocontrol the direction of action thereof, a latch cooperable, with thevalve-operating lever and acting when in latching position to retain thelever in one position and when in its released position to free thelever, and a thermostat subjected to the temperature in the compartmentand controlling the action of the latch.

3. In a refrigerator of the type including a chamber, a cooling coiltherein,.a compressor, and means, including a suction line, foroperatively interconnecting the cooling coil and the compressor, acontrol valve incorporated in the suction line and acting when open topermit flow therethrough and when closed to block all flow therethrough,latching means for releasably securing the valve inopen position,thermo-responsive means subjected to the temperature in the chamber andcoacting with said latch to release the same upon predetermined drop intemperature in the chamber and to move the same to latching positionupon predetermined rise of temperature in the chamber, mechanismoperable to open the valve and also operable to close the valve when thelatch is released, and thermo-responsive means subjected to thetemperature of the cooling coil for causing said.

mechanism to bias the valve to open position upon predetermined rise ofpressure in the coil and to closed position upon predetermined fall ofpressure therein.

4. In a refrigerator of the type including a chamber, a cooling colltherein, a compressor, and means, including a suction line, foroperatively interconnecting the cooling coil and the compressor, acontrol valve incorporated in the suction line and acting when open toprovide for flow through said line and when closed to stop all flowtherethrough, an operating lever for said valve, a reversible actiontoggle lever and spring.

combined with said lever and adjustable so as to cause the lever to biasthe valve either to open or to closed position, a thermostat subjectedto with said latch to release the latch upon predetermined fall oftemperature in the chamber and move it to latching position uponpredetermined rise of temperature therein.

5. In a refrigerator of the type including a chamber, a cooling coiltherein, a compressor, and

means, including a suction line, ,for operatively I interconnecting thecooling coil and compressor, a control valve incorporated in the suctionline between the cooling coil and the compressor and acting when, opento permit flow of refrigerant through said line and when closed to stopall' flow therethrough, latching means for releasably securing the valvein open position, means responsive to the temperature in the chamber forreleasing said latching means, mechanism operable, to open the valve andalso operable, when the latch is released, to close the valve, andtemperature-responsive means subjected to' the temperature of the coilfor controlling the action of said mechanism.

6. A vapor compression refrigerating machine including a chamber, acooling coil therein, a compressor, a suction line connecting thecooling coil and the compressor, a control valve incorporated in thesuction line and acting when open to permit flow therethrough and whenclosed to block all flow therethrough, a latch for releasably securingthe valve in open position, a spring for biasing the latch to releasedposition, a thermostat oi the expanding fluid type subjected to thetemperature in the chamber,

with said operating mechanism and opposing the action of said last-namedspring thereon.

'7. A vapor compression refrigerating machine I including a chamber, acooling coil therein, a compressor, a suction line connecting thecooling coil and the compressor, a control valve incorporated in thesuction line and acting when open ot permit flow therethrough and whenclosed to block all flow therethrough, a latch for releasably securingthe valve in open position, a spring for biasing the latch to releasedposition, manually operable means for varying the compression of thespring, a thermostat of the expanding fluid type subjected to thetemperature in the chamber and opposing the action of said spring,operating mechanism for the valve, a spring for biasing said operatingmechanism to a position to close the valve, manually adjustable meansfor varying the tension of said lastnamed spring, and a thermostat ofthe expanding fluid type subjected to the temperature of the coil andcoacting with the operating mechanism in such manner as to oppose theaction of its associated spring.

8. A vapor compression refrigerating machine including a chamber, 'acooling coil therein, a compressor, a suction line connecting thecooling coil and the compressor, a control valve incorporated in thesuction line and acting when open to permit flow therethrough and whenclosed to block all flow therethrough, means responsive to thetemperature of the chamber to hold the valve open. until the temperaturein the chamber -falls to a predetermined value and to release the valve,for closing movement when the temperature in the chamber has fallen tosaid predetermined value, and means responsive to coil tem-- pera'tureand eilective to close the valve when the valve is released for closingmovement by said first-named means and the temperature in the coil hasfallen to a predetermined value and also effective to open the, valvewhen the temperature of the coil rises to a predetermined value. v

9. A vapor compressionrefrigerating machine including a chamber, acooling coil therein, a

' compressor, a suction line connecting the coolmg coil and thecompressor, a control valve incorporated in the suction line and actingwhen open to permit flow therethrough and when closed to block all flowtherethrough, a latch cooperable with the valve and efiective, in itslatching position, to hold the valve open, and in its release positionto release the valve for closing movement, a thermostat responsive tothe temperature of the chamber and operatlvely interconnected with thelatch to shift the latch to latching position when the temperature inthe chamber rises to a predetermined degree and to a releasedposition'when the'temperature inthe chamber falls to a predetermineddegree, and a thermostat responsive to coiltemperature and operatlvelyinterconnected with the valve to close the valve when the latch is inreleased position and the'coil temperaturehas risen to a predeterminedvalue, and to open the valve when the coil temperature rises to apredetermined value.

ROY W. JOHNSON. CLARENCE L. AUGHEY.

